Image Caption : Dopamine Molecule : Dopamine is a neurotransmitter that is central to the brain network governing motivation, the sense of reward, and feelings of pleasure. Alterations to the dopaminergic system affect how people act on the inherent desire to seek out pleasure and avoid pain. It can be thought of as a biological cheerleader that tells a person to keep doing one thing, or stop doing another. Dopamine also helps regulate many of the systems of the body, including the kidneys and the heart.
Dopamine-mainly involved in controlling movement and aiding the flow of information to the front of the brain, which is linked to thought and emotion. It is also linked to reward systems in the brain. Problems in producing dopamine can result in Parkinson's disease, a disorder that affects a person's ability to move as they want to, resulting in stiffness, tremors or shaking, and other symptoms. Some studies suggest that having too little dopamine or problems using dopamine in the thinking and feeling regions of the brain may play a role in disorders like schizophrenia or attention deficit hyperactivity disorder (ADHD).
The National Institute of Mental Health (NIMH) / (NIH)
Dopamine is an organic chemical of the catecholamine and phenethylamine families that plays several important roles in the human brain and body, as well as elsewhere in biology. Its name derives from its chemical structure: it is an amine formed by removing a carboxyl group from a molecule of L-DOPA. In the brain, dopamine functions as a neurotransmitter—a chemical released by nerve cells to send signals to other nerve cells. The brain includes several distinct dopamine systems, one of which plays a major role in reward-motivated behavior. Most types of reward increase the level of dopamine in the brain, and a variety of addictive drugs increase dopamine neuronal activity. Other brain dopamine systems are involved in motor control and in controlling the release of various hormones.
Several important diseases of the nervous system are associated with dysfunctions of the dopamine system. Parkinson's disease, a degenerative condition causing tremor and motor impairment, is caused by loss of dopamine-secreting neurons in a midbrain area called the substantia nigra. There is evidence that schizophrenia involves altered levels of dopamine activity, and the antipsychotic drugs that are frequently used to treat it have a primary effect of attenuating dopamine activity. Attention deficit hyperactivity disorder (ADHD) and restless legs syndrome are associated with decreased dopamine activity.
Outside the nervous system, dopamine functions in several parts of the body as a local chemical messenger. In the blood vessels, it inhibits norepinephrine release and acts as a vasodilator (at normal concentrations); in the kidneys, it increases sodium excretion and urine output; in the pancreas, it reduces insulin production; in the digestive system, it reduces gastrointestinal motility and protects intestinal mucosa; and in the immune system, it reduces the activity of lymphocytes. With the exception of the blood vessels, dopamine in each of these peripheral systems has a "paracrine" function: it is synthesized locally and exerts its effects near the cells that release it.
A variety of important drugs work by altering the way the body makes or uses dopamine. Dopamine itself is available for intravenous injection: although it cannot reach the brain from the bloodstream, its peripheral effects make it useful in the treatment of heart failure or shock, especially in newborn babies. L-DOPA, the metabolic precursor of dopamine, does reach the brain and is the most widely used treatment for Parkinson's disease. Dopaminergic stimulants can be addictive in high doses, but some are used at lower doses to treat ADHD. Conversely, many antipsychotic drugs act by suppressing the effects of dopamine. Drugs that act against dopamine by a different mechanism are also some of the most effective anti-nausea agents.
The material on this site is for informational purposes only and is not intended as medical advice. It should not be used to diagnose or treat any medical condition. Consult a licensed medical professional for the diagnosis and treatment of all medical conditions and before starting a new diet or exercise program. If you have a medical emergency, call 911 immediately.